Trocar and seal arrangement

ABSTRACT

A trocar (2) includes a hollow body (4) defining a path between its proximal and distal ends with an obturator assembly (6) positioned along the path. The tip (34, 36) of the obturator assembly has a cutting element (38). A novel gas sealing assembly (114) seals the path along the trocar body and includes a pair of elastomeric, disc-like slit barriers (122, 124) having opposed, convex surfaces (128) and a flexible, elastic, conical element (136) with a hole (158) at its tip. The conical element and the proximal barrier (122) have raised ridges or rings (144, 164) along their inner surfaces (142, 154).

CROSS REFERENCE TO RELATED APPLICATION

This is related to U.S. patent application Ser. No. 08/015,170, filedFeb. 9, 1993 for TROCAR, the disclosure of which is incorporated byreference.

BACKGROUND OF THE INVENTION

Practitioners of medicine or surgery frequently advise a patient toundergo an invasive procedure for either diagnostic or therapeuticreasons. One such invasive procedure involves the use of a trocar whichis a sharpened cannula or cylindrical instrument for piercing the wallof a body cavity to minimize traumatization to the tissue through whichthe endoscopic instrument is passed and to stabilize such endoscopicinstrument as well as to provide a seal for insufflation of gasses toexpand the operating theater. Thus, the practitioner can gain access tothe cavity to withdraw a substance such as a fluid or biopsy specimen,to introduce a gas such as carbon dioxide or an instrument, such as asurgical tool. A laparoscope, a flexible fiberoptic endoscope, is anexample of a surgical instrument often introduced through a trocar. Thetrocar barrel also helps to avoid trauma to the tissue surrounding theopening while inserting and withdrawing a surgical instrument.

Any of the numerous body cavities can be accessible to trocar invasion.Sites for introduction of a trocar include the abdomen and the pelvis. Alaparoscope can be introduced through the trocar for visualization,biopsy, and certain surgical procedures. Other body cavities whichcommonly benefit from endoscopic procedure include the thoracic,cranial, and various joint cavities.

A general technique for introduction of a trocar includes induction ofappropriate anesthesia which may be general, local or a combination ofboth. The area to be pierced by the trocar, such as the skin of theabdomen, is prepped and cleansed conventionally. Typically, the operatormakes a nick or a small skin incision with a scalpel blade. Thesharpened tip of the conventional trocar is introduced through the nickor incision, and the conventional trocar is pushed downward to andthrough the fatty tissue. The conventional trocar is further pushed sothat its sharpened tip pierces the muscular fascial layer to enter theabdominal cavity.

In the case of laparoscopic surgery (surgery inferior to the diaphragm)a biocompatible gas such as carbon dioxide (CO₂) is introduced underpressure into the abdominal cavity to create a space between themuscular fascial layer of the inner abdominal wall and the vital organsposterior to this wall. Such vital organs in the abdomen include thebowel (large and small intestine), the liver, stomach and otherstructures. Use of CO₂ insufflation of the pelvic region tends toprotect the bladder and the reproductive organs as well as theirassociated vascular structures from inadvertent puncture by thesharpened trocar. This is so because of the increased separation betweenthe organs resulting from the expansion of the abdominal cavity due tointernal CO₂ gas pressure.

SUMMARY OF THE INVENTION

The present invention is directed to a seal for use with medical devicesdesigned for minimally invasive surgical procedures. The medical deviceis of the type having a hollow interior defining a path which is to befluidly sealed both when an object has and has not been directed alongthe path and into the hollow interior. The invention finds particularutility when used as a part of a trocar.

The seal is used for sealing the path along the body of a trocar. Theseal seals the path both when the obturator or any surgical device iswithin the trocar body and once the obturator/surgical device has beenremoved from the trocar body. The seal includes a flexible, elastic,conical valve element tapering inwardly towards the distal end of thetrocar body. The seal also includes first and second flexible, elasticbarriers having abutting convex surfaces with offset slits formedtherein. The conical valve element is designed to engage the outside ofthe obturator/surgical instrument to provide a fluid seal along the pathwhen such objects are housed within the trocar body. The first andsecond slit barriers are designed to provide a fluid seal along the pathwhen the obturator/surgical instrument is removed from the trocar body.

The region of the hollow interior distal of the conical element ispreferably selectively coupled to a pressurized gas source and toatmosphere. This allows the physician to pressurize or vent the bodycavity through the trocar. It is preferred that the material for thebarriers and the conical element be chosen and the elements beconfigured to accommodate a range of diameters from, for example, 5 mmto 11.4 mm, that is a range in diameters from x to at least 2×. Also,when configuring the object-engaging surfaces and choosing the material,care must be taken to minimize the amount of force required to past theinstrument through the gas seal.

The conical sealing element is designed to accommodate an obturatorassembly and virtually any conventional endoscopic surgical instrumentwhich would be used with the trocar body after the trocar body has beenmounted in place. One of the problems with known trocars is that the gasseals are designed for the obturator assembly and similarly sizedendoscopic surgical instruments. However, many endoscopic surgicalinstruments are substantially smaller in diameter than the obturatorassembly. When this occurs, the instrument can often move radiallywithin the barrel of the conventional trocar body which can cause a lossin sealing effectiveness of the conventional gas seal. To accommodatethese smaller diameter surgical instruments, conventional trocars mayuse smaller diameter positioning and sealing inserts mounted to theconventional trocar body at its proximal end.

The present invention has solved these problems by designing the conicalsealing element within an included angle of between about 60° and 120°,preferably about 90°, and making the conical sealing element of a highlyelastic, yet tough material. A suitable material has been found to be 50Durometer silicone rubber. The hole at the tip of the conical sealingelement is at most about 90% of the smallest diameter arthroscopicsurgical instrument expected to be used. In the preferred embodiment thehole is about 4.6 mm in diameter. The conical sealing element isdesigned to accommodate obturator/surgical instruments having diametersranging in size from at least 2 to 1 and preferably 3 to 1. In thepreferred embodiment the ranges of sizes range from about 5 mm to atleast 10 mm and preferably up to 15 mm.

The conical sealing element and the slit barriers are designed to reduceaxial friction on the obturator/surgical instruments which are passedthrough the trocar body. It has been found by placing a series of raisedridges or rings along the inner surfaces of the conical sealing elementand the proximal slit barrier, the axial friction generated between thesurgical instrument and the conical sealing element/slit barriers can besubstantially reduced, thus increasing operational sensitivity for thephysician.

Other features and advantages of the invention will appear from thefollowing description in which the preferred embodiment has been setforth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall isometric view of a trocar made according to theinvention;

FIG. 2 is an exploded isometric view of the trocar of FIG. 1;

FIGS. 3A and 3B are cross-sectional views of proximal and distalportions of the trocar of FIG. 1;

FIG. 4 is a cross-sectional view of the trocar body of FIGS. 1 and 2;

FIGS. 5, 5A and 5B are cross-sectional views of the conical sealingelement in its unstressed state of FIG. 4 and with a larger and smallerdiameter tubes passing therethrough, respectively; and

FIGS. 6A and 6B are plan cross-sectional views of the trocar body andelastomeric vent ring of FIG. 4 shown with pressurized fluid passinginto the interior of the trocar body in FIG. 6A and the opening of avent path to the ambient environment in FIG. 6B.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1-3B illustrate a trocar 2 including a trocar body 4 to and withinwhich an obturator assembly 6 is slidably mounted. Trocar body 4 ishollow and includes a trocar base 8 to which a tubular trocar barrel 10is secured, such as with an adhesive. Trocar barrel 10 defines a centralaxis 12 of trocar 2 and is sized to guide the obturator barrel 14therein.

Obturator assembly 6 includes an obturator barrel 14 having a flangedproximal end 16 and a distal end 18. An idler pulley support 20 ismounted to proximal end 16 using a pin 22 which passes through openings24 formed in barrel 14 at proximal end 16 and bores 26 in legs 28 ofidler pulley support 20. Pin 22 also supports an idler pulley 30 betweenlegs 28 of idler pulley support 20. A cutting tip assembly 32 is mountedto distal end 18 of obturator barrel 14. Assembly 32 includes a pair ofobturator tip shells 34, 36 and a blade 38 rotatably mounted on an axle40 extending between tip shells 34, 36. Blade 38 has a spirally groovedouter surface 42 to accommodate one or more windings of a continuousloop cable 43. Cable 43 is thus stretched between surface 42 of blade 38and idler pulley 30 and is housed totally within obturator barrel 14.

Upper and lower limit flanges 44, 46 are secured to obturator barrel 14at fixed positions, such as using an adhesive. Flanges 44, 46 haveradially extending tabs 48, 50 which are housed within slots 52, 54formed in the sidewall 56 of an obturator body 58. By the engagement oftabs 48, 50 within slots 52, 54, obturator barrel 14 is mounted withinbody 58 but is capable of relatively short axial movement for thepurposes to be discussed below. Obturator barrel 14 is biased in adistal direction 59 within obturator body 58 by an actuation forceadjustment spring 60. Spring 60 is captured between an actuation forceadjustment screw 62, housed within a threaded hole 64 formed in theproximal end 66 of body 58, and idler pulley support 20.

Cable 43 is moved, thus rotating blade 38, through the use of a cuttingelement driver 68. Driver 68 includes a cable clamp 70 which is clampedto cable 43 in the region adjacent a longitudinal slot 72 formed inobturator barrel 14. Cable clamp 70 is sized to fit within slot 72 andto move axially along the slot. Cable clamp 70 also includes alongitudinally extending slot or gap 74 which houses cable 43. Cableclamp 70 is secured to a generally tubular shuttle 76 which slidesaxially along obturator barrel 14. Shuttle 76 and cable clamp 70 eachhas a set of three aligned holes 78, 80 within which a set of screws 82are mounted. Holes 78 in cable clamp 70 are threaded only in their endsfarthest from holes 80; holes 80 and the remainder of holes 78 arethrough holes. Accordingly, tightening screws 82 cause cable clamp 72squeezed tightly onto cable 43. Because of the engagement of cable clamp70 within slot 72, the axial movement of cable clamp 70 and shuttle 76is limited by the axial length of slot 72. Accordingly, the distancecable 43 can move is likewise so limited. Slot 72 is sized so that blade38 makes one revolution when cable clamp 70 moves from one end of slot72 to the other end.

The driving force behind cutting element driver 68 is provided by bladedrive spring 84 which is captured between upper limit flange 44 and aradially extending flange 86 at the base of shuttle 76. Spring 84 thusnormally biases shuttle 76 in distal direction 59. By moving shuttle 76in a proximal direction 87, thus compressing spring 84 between flange 86and upper limit flange 44, the unit can be armed. This armed conditionis retained through the use of a pair of latching arms 88 pivotallymounted to shuttle 76 adjacent flange 86 by pins 90. In the armed orpre-use condition of FIGS. 1 and 3A, ledges 92 of latching arms 88engage the proximal surface 94 of upper limit flange 44 thus keepingspring 84 compressed. Latching arms 88 are released from upper limitflange 44 by the axial movement of obturator assembly 6 in proximaldirection 87. This occurs when an inwardly extending release ring 95,extending inwardly from proximal end 66 of obturator body 58, engagesangled camming surfaces 96 of latching arms 88 thus rotating arms 88radially outwardly disengaging latching arms 88 from upper limit flange44 thus permitting spring 84 to drive shuttle 76 and cable clamp 70therewith in distal direction 59 along slot 72. This axial movement ofcable clamp 70 causes similar movement of cable 43 causing blade 38 torotate one revolution. As suggested in FIGS. 1 and 3B, blade 38 issafely housed within tip shells 34, 36 both when in the pre-use, armedcondition of FIGS. 1 and 3B and after actuation, due to the appropriatesizing of slot 72.

Trocar body 4, see FIGS. 3A and 4, includes a locking plate 98 having ahollow cylindrical boss 100 sized to fit within the tubular proximal end102 of trocar base 8. Locking plate 98 has a pair of tapered latchingsurfaces 108 positioned above and radially outwardly of proximal end 102of base 8. Latching surfaces 108 are sized to accommodate the distalends of resilient docking hooks 112 at the distal end of obturator body58. Placing the distal end of obturator body 58 against locking plate98, shown in FIGS. 1 and 3A, causes docking hooks 112 to engage latchingsurfaces 108, to be biased inwardly and then to snap outwardly to latchbeneath surfaces 108 thus securing obturator assembly 6 to trocar body4.

Trocar body 4 includes a sealing assembly 114 mounted within theproximal, enlarged cylindrical portion 116 of trocar base 8 and anelastomeric vent ring 118 positioned adjacent an inwardly and distallytapering region 120 at the distal end of trocar base 8. Sealing assembly114 includes first and second elastomeric slit barriers 122, 124,preferably made from 50 Durometer silicone rubber. Each barrier 122, 124has a cruciform slit 126 formed through its middle. Slit 126 of barriers122, 124 are shifted 45° from one another so that the slits overlie oneanother only at their very centers. As seen in FIG. 4, barriers 122, 124are both shallow, cup-shaped members having opposed convex surfaces 128which meet at their centers. Boss 100 fits within the interior 130 ofbarrier 122 and captures the circumferential wall 132 of barrier 122between boss 100 and cylindrical portion 116 of trocar base 8. Boss 100is sized to provide a tight, secure fit of locking plate 98 to proximalend 102 of trocar base 8.

A spacer ring 134 is mounted between slit barrier 124 and a conicalsealing element 136. Sealing element 136 is held in place by aproximally facing ledge 138 formed in base 8. Ledge 138 is positioned sothat surfaces 128 of barriers 122, 124 abut and deflect one anothersomewhat as suggested in FIG. 4. This helps to ensure that slits 126remain closed, thus sealing the interior 140 of trocar base 8 againstfluid flow. It has been found that making barriers 122, 124 having anoutside diameter of 22.4 mm, a thickness of 1.4 mm, slits about 11.1 mmlong and a radius of 15 mm and then deflecting each barrier about 0.5 mmprovides an effective seal for the pressures typically encountered inlaparoscopic surgery, typically about 15.5 mm Hg (0.3 psi).

Inner surface 142 of slit barrier 122 has a number of concentricupraised rings 144 used to reduce sliding friction between slit barrier122 and an obturator barrel 14, or a surgical instrument, passed throughtrocar body 4. In the preferred embodiment, raised rings are spacedabout 3.0 mm apart and about 0.5 mm high. It has been found that thisconfiguration provides substantial, in the range of 20% to 50%,reduction in frictional force when used with an obturator barrel 14having a diameter of 11.1 mm. Inner surface 146 of barrier 124 is notridged like surface 142.

Conical sealing element 136, see FIG. 5, is preferably made from a 50Durometer silicone rubber for its toughness and good sealing qualities.Conical sealing element 136 includes an outer flange 148 surrounding amain cylindrical portion 150 and, continuing in distal direction 59, aninwardly and distally directed conical portion 152. Conical portion 152has an inner conical surface 154 defining an included angle of about 90°in the preferred embodiment. Conical portion 152 has an outer conicalsurface 156 defining an included angle of about 106° so that conicalportion 152 has a mean included angle of about 98° and a wall taper ofabout 8°.

Conical portion 152 has an opening 158 at a distal end thereof sized tobe somewhat smaller than the smallest diameter object, typically anobturator or surgical instrument, expected to pass therethrough. In thepreferred embodiment this diameter is approximately 4.6 mm. The insidediameter of cylindrical portion 150 is about 15 mm. FIGS. 5A and 5Billustrate different diameter tubes 160, 162 passing through conicalsealing element 136. Tubes 160, 162 represent different diameterobjects, typically endoscopic surgical instruments which can be passedthrough trocar barrel 10 once obturator assembly 6 is removed fromtrocar body 4. Tube 160 has an outer diameter of about 10 mm while tube162 has an outside diameter of about 5 mm. It has been found that theparticular configuration of conical portion 152 of conical sealingelement 136 provides a good gas seal over a range of sizes of objectsused within trocar body 4. In the example of FIGS. 5A and 5B, there is2:1 ratio between the larger tube 160 and the smaller tube 162. Sincethe inside diameter of cylindrical portion 150 is about 15 mm, the rangeof diameters of objects which can be used with the invention can be asgreat as about 3:1 with this embodiment.

As can be seen in FIGS. 5-5B, inner surface 154 has a series of raisedring-like ridges 164 formed thereon. Ridges 164 are, like rings 144,used to reduce sliding friction, for example of tubes 160, 162 passingthrough conical sealing element 136. In the preferred embodiment, 8generally evenly spaced rings, each about 0.5 mm high, are used. Ifdesired, surfaces 142, 154 can be made with a low-friction surfacematerial or a biocompatible lubricant to reduce sliding friction andthus minimize loss of sensitivity to the physician when manipulating theinstrument.

Vent ring 118, see FIGS. 6A and 6B, is made from an elastomericmaterial, such as 50 Durometer silicone rubber, and includes an integralconical check valve 166 which is aligned with a radially extending Luerlock fitting 168 mounted within a hole 176 in base 8. A remote pressuresource (not shown) is connected to fitting 168. Check valve 166 allowsfluid to pass into interior 140 of body 8, as suggested in FIG. 6A, butnot the reverse, as suggested in FIG. 6B. Base 8 has a radiallyextending bore 170 through which a radial extension 172 passes. Theenlarged base 174 of extension 172 is biased against bore 170 withsufficient force to normally seal bore 170. To vent interior 140, theuser simply presses on extension 172 which deflects ring 118 radiallyinwardly as shown in FIG. 6B. This provides a vent path from interior140 to the ambient environment through bore 170. Accordingly, with theinvention separate medical devices need not be used to either pressurizeor vent the body cavity accessed by trocar 2.

The final element of trocar body 4 is a finger ledge 182. Finger ledge182 is secured to the outside of base 8 adjacent external ledge 184,such through an adhesive or using a friction fit.

The present invention is made from conventional biocompatible materials.For example, blade 38, springs 68, 84, cable 43 plus the various pinsand screws are preferably made from stainless steel. Barriers 122, 124,conical element 136 and vent ring 118 are preferably made of a suitableelastomeric material, as discussed above. The remaining parts can bemade of polycarbonate or other appropriate materials. It is particularlyimportant that trocar base 8 and trocar barrel 10 be made ofbiocompatible materials.

In use, the physician first makes a small incision with a scalpel at thepoint of entry. The tapered tip of obturator 10 is then pressed throughthe slit in the patient's skin, through the fatty tissue layer until thetip reaches the muscular fascial layer. At this point, further force ontrocar 2 causes obturator assembly 6 to move proximally causing latchingarms 88 to be pivoted outwardly to permit cable clamp 70 to be drivendistally by spring 84 thus rotating blade 38 one revolution and making alinear incision through the patient's fascial layer. With blade 38safely stowed back between tip shells 34, 36, the physician continues toforce obturator assembly 10 through the newly created incision in thefascial layer so to properly position trocar barrel 10 within the bodycavity of the patient. Obturator assembly 6 is then removed from trocarbody 4 by pressing on docking hooks 112 and lifting the obturatorassembly in proximal direction 87. As the tip of obturator assembly 6passes through conical element 136, the conical element returns to itsopen, unflexed condition of FIGS. 4 and 5. As the tip of obturatorassembly 6 passes barriers 124, 122, the barriers return to theirsealing positions of FIG. 4 to prevent escape of fluid pressure throughtrocar 2. An endoscopic surgical instrument, such as an endoscope, canthen be inserted through trocar body, past gas seal 114, through theinterior 186 of trocar barrel 10 and into the body cavity. The surgicalinstrument is surrounded by surface 154 of conical element 136 to helpprevent the loss of pressurization within the body cavity. The bodycavity can be pressurized by simply mounting a pressurized line tofitting 168 and supplying pressurized fluid, typically CO₂, intointerior 140, through interior 186 and into the body cavity. Thepressure in the body cavity can be reduced by pressing on extension 172which deflects vent ring 118 and permits fluid flow through bore 170 andto the ambient environment.

Modifications and variations can be made to the disclosed embodimentwithout departing from the subject of the invention as defined in thefollowing claims. For example, sealing assembly 114 could be used withother medical devices designed for minimally invasive surgicalprocedures. Also, slits 126 need not be straight and could be at anangle to a plane perpendicular to axis 12. The proximal/distalrelationship of barriers 122, 124 and conical sealing element 136 couldbe reversed.

What is claimed is:
 1. A medical device, designed for minimally invasivesurgical procedures, comprising:a body having proximal and distal endsand a hollow interior defining a path between the proximal and distalends; an object sized to pass along the path; and a seal mounted withinthe body and fluidly sealing the path with and without the objectdirected along the path and into the hollow interior, the sealincluding:first and second flexible, elastomeric barriers positionedalong the path, the barriers having opposed convex surfaces, thebarriers being positioned so the center of the opposed surfaces abut anddeflect each other, the barriers each having at least one normallyclosed slit formed therein, said slit in the first barrier being at adifferent orientation from the slit in the second barrier, said barriersconfigured to permit the object to pass therethrough and to provide afluid seal when the object is not positioned along the path; and anobject seal, positioned along the path, configured to sealably engagethe object when the object is directed along the path to provide a fluidseal between the object and the hollow interior.
 2. The medical deviceof claim 1 wherein the object seal includes:a flexible, elastic, conicalelement, positioned along the path, tapering inwardly from a first endin a direction from the proximal end of the body towards the distal endof the body, the conical element including a central opening at a secondend thereof, the central opening, when the conical element is in arelaxed, contracted state, having a diameter which is at least slightlysmaller than the diameter of the object to provide a fluid seal betweenthe object and the hollow interior.
 3. The medical device of claim 2wherein the object has a first diameter, the conical element beingadapted to engage a large object having a second diameter at least twiceas large as the first diameter.
 4. The medical device of claim 1 whereinthe object is an obturator.
 5. The medical device of claim 4 wherein thecruciform patterns are radially centered on one another.
 6. The medicaldevice of claim 4 wherein the cruciform patterns are radially centeredwithin the hollow interior.
 7. The medical device of claim 1 wherein themedical device is a trocar.
 8. The medical device of claim 1 wherein thefirst and second barriers each have at least two of said slits orientedat 90° to each other to form a cruciform pattern, the cruciform patternof the first barrier being rotated about 45° from the cruciform patternof the second barrier.
 9. A medical device, designed for minimallyinvasive surgical procedures, comprising:a body having proximal anddistal ends and a hollow interior defining a path between the proximaland distal ends; an object sized to pass along the path; and a sealmounted within the body and fluidly sealing the path with and withoutthe object directed along the path and into the hollow interior, theseal including:first and second flexible, elastic barriers positionedalong the path, the barriers having opposed surfaces, the barriers beingpositioned so the opposed surfaces touch, the barriers each having atleast one normally closed slit formed therein, said slit in the firstbarrier being at a different orientation from the slit in the secondbarrier, said barriers configured to permit the object to passtherethrough and to provide a fluid seal when the object is notpositioned along the path; and a flexible, elastic, conical element,positioned along the path, tapering inwardly from a first end in adirection from the proximal end of the body towards the distal end ofthe body, the conical element including a central opening at a secondend thereof, the central opening, when the conical element is in arelaxed, contracted state, having a diameter which is at least slightlysmaller than the diameter of the object to provide a fluid seal betweenthe object and the hollow interior, the conical element having an innersurface with a series of raised elements thereon.
 10. A medical device,designed for minimally invasive surgical procedures, comprising:a bodyhaving proximal and distal ends and a hollow interior defining a pathbetween the proximal and distal ends; an object sized to pass along thepath; and a seal mounted within the body and fluidly sealing the pathwith and without the object directed along the path and into the hollowinterior, the seal including:first and second flexible, elastic barrierspositioned along the path, the barriers having opposed surfaces, thebarriers being positioned so the opposed surfaces touch, the barrierseach having at least one normally closed slit formed therein, said slitin the first barrier being at a different orientation from the slit inthe second barrier, said barriers configured to permit the object topass therethrough and to provide a fluid seal when the object is notpositioned along the path; the first barrier being positioned proximallyof the second barrier, the first barrier having a proximal surfacefacing away from the second barrier, the proximal surface having raisedelements thereon; and an object seal, positioned along the path,configured to sealably engage the object when the object is directedalong the path to provide a fluid seal between the object and the hollowinterior.
 11. A medical device, designed for minimally invasive surgicalprocedures, comprising:a body having proximal and distal ends and ahollow interior defining a path between the proximal and distal ends; anobject sized to pass along the path; and a seal mounted within the bodyand fluidly sealing the path with and without the object directed alongthe path and into the hollow interior, the seal including:first andsecond flexible, elastic barriers positioned along the path, thebarriers having opposed surfaces, the barriers being positioned so theopposed surfaces touch, the barriers each having at least one normallyclosed slit formed therein, said slit in the first barrier being at adifferent orientation from the slit in the second barrier, said barriersconfigured to permit the object to pass therethrough and to provide afluid seal when the object is not positioned along the path; an objectseal, positioned along the path, configured to sealably engage theobject when the object is directed along the path to provide a fluidseal between the object and the hollow interior; a resilient vent ring,having an interior surface and an exterior surface, mounted along thepath within the hollow interior of the body between the object seal andthe distal end of the body; a passageway formed from the interiorsurface, through the body and to a port exterior of the body; a checkvalve positioned along the passageway to permit fluid flow through theport, along the passageway and into the hollow interior but to preventfluid flow from the hollow interior, through the passageway and throughthe port; and a vent ring deflector extending from the vent ring througha vent in the body to a user-accessible position exterior of the body,the vent ring deflector movable from a normally sealed position, atwhich the vent ring and vent ring deflector seal the vent to preventfluid flow from the hollow interior and through the vent, to a ventposition, at which the vent ring is deflected inwardly into the hollowinterior to permit fluid flow from the hollow interior, through the ventand into a region exterior of the body.
 12. The medical device of claim11 wherein the vent ring is made of an elastomeric material.
 13. Themedical device of claim 11 wherein the check valve is a one-pieceelement with the vent ring.
 14. The medical device of claim 11 whereinthe port is part of a Luer lock fitting.
 15. The medical device of claim11 wherein the vent ring deflector extends radially from the vent ringand is a one-piece extension of the vent ring.
 16. A trocar comprising:abody having proximal and distal ends and a hollow interior defining apath between the proximal and distal ends; an object sized to pass alongthe path; and a seal mounted within the body and fluidly sealing thepath with and without the object directed along the path and into thehollow interior, the seal including: first and second flexible, elasticbarriers positioned along the path, the barriers having opposed convexsurfaces, the barriers being positioned so the opposed convex surfacestouch; the first and second barriers each having at least two of saidslits oriented at an angle to each other to form first and second slitpatterns on the first and second barriers respectively, the first slitpattern of the first barrier rotated relative to the second slit patternof the second barrier, said barriers configured to permit the object topass therethrough and to provide a fluid seal when the object is notpositioned along the path; the first barrier being positioned proximallyof the second barrier, the first barrier having a proximal surfacefacing away from the second barrier, the proximal surface having araised ring-like elements thereon; a flexible, elastic, conical element,positioned along the path, tapering inwardly from a first end in adirection from the proximal end of the body towards the distal end ofthe body, the conical element including a central opening at a secondend thereof, the central opening, when the conical element is in arelaxed, contracted state, having a diameter which is at least slightlysmaller than the diameter of the object to provide a fluid seal betweenthe object and the hollow interior; the conical element has an innersurface and the inner surface has a series of raised ring-like elementsthereon; and the conical element being adapted to engage objects havingoutside diameter of x to at least 2×.
 17. A seal, for use with asurgical object and hollow body defining a path, the surgical object andthe body being used in a minimally invasive surgical procedure, the bodyhaving proximal and distal ends, comprising:first and second flexible,elastic barriers positioned along the path, the barriers having opposedsurfaces, the barriers being positioned so the opposed surfaces touch,the barriers each having at least one normally closed slit formedtherein, said slit in the first barrier being at a different orientationfrom the slit in the second barrier, said barriers configured to permitthe surgical object to pass therethrough and to provide a fluid sealwhen the object is not positioned along the path, the first barrierbeing positioned proximally of the second barrier, the first barrierhaving a proximal surface facing away from the second barrier, theproximal surface having raised ring-like elements thereon.
 18. The sealof claim 17 wherein at least one of the opposed surfaces is a convexsurface.
 19. The seal of claim 17 wherein the first and second barrierseach have at least two of said slits oriented at 90° to each other toform a cruciform pattern, the cruciform pattern of the first barrierbeing rotated about 45° from the cruciform pattern of the secondbarrier.
 20. A seal, for use with a surgical object and hollow bodydefining a path, the surgical object and the body being used in aminimally invasive surgical procedure, the body having proximal anddistal ends, comprising:first and second flexible, elastic barrierspositioned along the path, the barriers having opposed surfaces, thebarriers being positioned so the opposed surfaces touch, the barrierseach having at least one normally closed slit formed therein, said slitin the first barrier being at a different orientation from the slit inthe second barrier, said barriers configured to permit the surgicalobject to pass therethrough and to provide a fluid seal when the objectis not positioned along the path; and a flexible, elastic, conicalelement, positioned along the path, tapering inwardly from a first endin a direction from the proximal end of the body towards the distal endof the body, the conical element including a central opening at a secondend thereof, the central opening, when the conical element is in arelaxed, contracted state, having a diameter which is at least slightlysmaller than the diameter of the object to provide a fluid seal betweenthe object and the hollow body, the conical element having an innersurface and the inner surface having a series of raised ring-likeelements thereon.
 21. The seal of claim 20 wherein the object has afirst diameter, the conical element adapted to engage a large objecthaving a second diameter at least twice as large as the first diameter.